Delta Lithium has successfully produced battery-grade lithium carbonate and high-grade rubidium carbonate from mica concentrate at its Mt Ida project, confirming strong recovery rates and potential new revenue streams.
- 99.8% pure lithium carbonate produced, suitable for battery manufacturing
- 86% lithium recovery and 67% rubidium recovery from mica concentrate
- Rubidium carbonate product grades at ~97% purity
- Mt Ida project holds significant lithium, tantalum, and rubidium JORC resources
- Company cash position of $52M plus $100M in ASX-listed investments
Breakthrough in Downstream Processing
Delta Lithium Limited (ASX:DLI) has announced a significant milestone in the development of its Mt Ida Lithium Project in Western Australia. Recent hydrometallurgical testwork on the mica concentrate; a byproduct typically discarded before spodumene flotation; has yielded high-purity lithium carbonate (99.8%) and rubidium carbonate (~97% Rb2CO3). These results confirm the concentrate’s suitability for battery manufacturing and open the door to additional revenue streams from rubidium, a critical mineral.
The testwork demonstrated an impressive 86% lithium recovery and 67% rubidium recovery from the mica concentrate, underscoring the efficiency of the newly developed flowsheet chemistry. This is a notable achievement given the complexity of extracting these elements from mica, which contains a mixture of lithium, rubidium, potassium, and other gangue minerals.
Strategic Importance of Rubidium
Rubidium is a relatively rare alkali metal, and Mt Ida’s lepidolite mica contains unusually high concentrations due to substitution of potassium with rubidium in the crystal lattice. The company’s ability to produce a high-grade rubidium carbonate product positions Delta Lithium as a potential supplier in a niche but strategically important market. Rubidium is listed as a critical mineral by the USA and Japan, reflecting its growing demand in advanced technologies and specialty applications.
Delta’s Managing Director, James Croser, highlighted the significance of this development: "The successful production of saleable lithium and rubidium carbonates from what was previously considered waste material creates a compelling opportunity to enhance project economics." The company plans to incorporate this byproduct revenue into its financial modelling for Mt Ida, potentially boosting the project’s overall value.
Robust Project Fundamentals and Financial Position
The Mt Ida Project boasts a substantial JORC-compliant mineral resource estimate, including 14.8 million tonnes at 1.2% lithium oxide, alongside tantalum and rubidium grades. This resource base, combined with the flowsheet’s whole-of-ore flotation approach, supports efficient lithium recovery and now, with the new testwork, enhanced value extraction from mica concentrates.
Financially, Delta Lithium is well positioned with a cash balance of approximately $52 million and an additional $100 million in ASX-listed investments. This strong balance sheet provides the company with the flexibility to advance further metallurgical optimisation and pilot testing, which are planned to improve recovery rates and demonstrate steady-state processing.
Next Steps and Market Implications
Looking ahead, Delta Lithium intends to refine the solvent extraction process to improve rubidium-potassium separation and conduct continuous closed-circuit piloting to validate the process at scale. Dewatering tests on products and tailings will also be undertaken to optimise operational efficiency.
With spodumene concentrate prices stabilising above US$2,000 per tonne, the timing for advancing Mt Ida’s development is favourable. The addition of rubidium byproduct revenue could provide a competitive edge in the lithium market, especially as demand for battery materials and critical minerals continues to grow globally.
Bottom Line?
Delta Lithium’s breakthrough in recovering high-purity lithium and rubidium from mica concentrate could redefine Mt Ida’s project economics and market positioning.
Questions in the middle?
- How will the inclusion of rubidium byproduct revenue impact Mt Ida’s overall project valuation?
- What are the timelines and costs associated with scaling up the hydrometallurgical process to commercial production?
- How sensitive is the project’s economics to fluctuations in rubidium market demand and pricing?